The rules for doubles are the same as singles, except the wider court is used.
Players within a pair do not have to hit alternate shots.
However, the serve rotates so that each player serves once every fourth game.
For instance from Player A in Pair A, to Player B in pair B, back to Player C in Pair A and then to Player D in Pair B.
Players can only change the order of serving and receiving at the end of a set.
The server's partner and the receiver's partner may stand anywhere they like on the court during the serve, even if it obstructs play.
Traditionally however, each player takes one side of the court.